Proteactoe



Jan. 12, 1954 P 2,665,482

PROTRACTOR Filed July 2, 1952 ,r INVENTOR' 6' 1.1623 riJ/Zv v BY fl/Z4 L/ ATTORNEY Patented Jan. 12, 1954 UNITED STATES PATENT OFFICE PROTRACTOR Albert J. Rupp, South Egg Harbor, .N..J. Application July 2, 1952, Serial No. 296,845

1 Claim.

My invention relates to new and useful improvements in protractors, and especially to provide a protractor that is to be used by carpenters, masons, and other artisans, in laying out lines in a lot or field, etc., as distinguished from the ordinary protractor that is used on a drawing board.

As is well known to those skilled in the art, before a building is erected on a lot, the lot is generally surveyed to mark out the boundary lines. After this the surveyor may lay out the other lines for the walls or the trenches or ditches, etc. This is more or less expensive and often the carpenter or other artisans will measure off a line from the base line that the surveyor has established and then lay a square against this line and against, say, a rearwardly extending line to define a line extending at right angles to the base line.

This method, however, is not very accurate because when the square is laid against a stretched line or between two stretched lines, the lines will give and the side wall, for instance, will not be exactly at right angles with the front line or base line.

One of the objects, therefore, of the present invention is to provide a protractor that is laid and supported on the base line string, and then the other arm of the protractor may be placed on a rearwardly extending string.

When the protractor shows that the two strings are exactly at right angles to each other, for instance, a stake will be driven, and the rearwardly extending string will be nailed to this stake, which, if a corner is being defined, will be the central stake of the batterboard; and, by the use of this protractor, the rearwardly extending string will be exactly at right angles to the string defining the base line.

Another object of the invention is to provide a relatively light protractor with but two movable parts, easily assembled, and wherein the protractor may be moved along the base line string in either direction; and the other string may be positioned at either right angles. or any other desired angle to the base line string.

With these and other objects in view, the invention consists in certain new and novel features and combinations of parts as will be hereinafter more fully described and pointed out in the claim.

Referring now to the drawings,

Fig. 1 is a plan View of my improved protractor as supported on a base line string and another string to define a line, the dotted lines showing the one arm of the position,

Fig. 2 is an enlarged, sectional view, taken on line 22 of Fig. 1,

Fig. 3 is a sectional view taken on line 3-3 of Fig. 1,

Fig. 4 is a fragmentary perspective of an end of either of the two arms, and

Fig. 5 is a plan view of the protractor in its folded or collapsed position.

Referring now more particularly to the drawings, there is shown a cross-arm l, which consists of a light metal strip having its one end bent down as at 2 and its other end similarly bent The metal of the downwardly bent end 2 is slit as at '4 and then bent over to form the arcuated guide 5, as may be seen clearly in Figs. 2 and 4. In the same way, the other end is bent in a similar manner to form the guide 6.

There is also shown an arcuated or semicircular piece or strip of metal 1, riveted as at 8 to the arm I; and this semi-circular strip 1 is bent downwardly as at 9 so that the strip 1 will another arm about to be mentioned. This strip 1 is graduated in degrees at I0, and it will be noticed that at 90 it is, of course, at exactly right angles to the arm I.

As may be seen in Fig. 1, this cross-arm I is riveted to the longer arm II, which arm II has its upper end bent downwardly as at I2, and the other end as at I3; and at the one end there is a guide I4 and at the other end the guide I5, which are similar to the heretofore mentioned guides 5 and 6 on the cross-arm I.

The cross-arm I is pivotally secured on the upper face of the arm II by the rivet l6 and there may -be a small washer I1 interposed between the two arms I and I I so that the arm I I may swing freely with respect to the arm I.

On the face of the arm II near the semicircular strip 1 is the marker I8, which is stamped centrally with respect to the width of the arm II so that when the arm I and the arm I I are at right angles the marker I 8 will be opposite the numeral 90 as shown in Fig. 1.

The manner in which the protractor is used is exceedingly simple and therefore just a brief desoription is set out.

Supposing the base line I9 has been established say, twenty-five feet (25') from the curb line and parallel thereto, the base line string I9 will be nailed to a post or stake 20 at the one end and to another stake (not shown) at the other end. The base line string I9 should extend beyond where the line for the side wall is to be laid out protractor in an angular to allow for the length of the cross-arm i from the longer arm ll.

Now, to lay out the line (string) for, we will say a Side wall, the string 2! will be nailed in the exact point desired along the base line and will be stretched rearwardly, and the arm II will be supported by this string 2!, the string 2| passing through the guides M and P5 in the same way that the string [9 passes through the guides 5 and 6.

Then the artisan holding the string 2! at its upper end (see Fig. 1) will move either to the right or left until the artisan at the other end of the string 2!, looking at the protractor, will see that the marker l8 is directly opposite the 90 mark. The string 25 will then be nailed tightly to a stake of the batterboard, and in this way the side wall or side line will be accurately set at right angles to the base line.

Should it be desired to have a line at an angle other than the 90, the method is, of course, just the same.

When the protractor is not in use it may be folded to the position shown in Fig. 5, thus occupying but little space in the tool box.

From the foregoing it will be seen that I have provided a protractor that may be made out of metal or plastic, and consisting of but two arms pivoted to each other, and the ends bent to form guides and supports so that the protractor may rest right on the two strings employed; and also that the line to be established from the base line may be quickly and readily determined and thus save the cost of having a surveyor with a transit lay out the lines.

It will be understood that. other might be formed on the ends of the arms,

forms of guides but I have found that the protraotor as shown is very eflicient in service, as the guides may be formed when the metal arms are stamped or molded.

Finally, although I have only mentioned the protractor for outlining walls, it may be used for laying out lines for any purpose after a base line or other line is established; and by sliding the protractor along the base line string any intermediate lines within the boundary may be established and at any angle desired.

Having thus described my invention, what I claim is new and desire to secure by Letters Patent is:

In a foldable protractor, to be supported on the stop of strings, for laying out lines, a long arm, a short arm, pivotally mounted thereon; a semi-circular indicator, graduated in degrees, secured to the short arm and bent downwardly to contact with the long arm; a marker on the long arm to indicate the angle between the two said arms; the outer ends of each of the arms bent downwardly and then outwardly to form identical arcuate guides, the said guides adapted to rest on the top of strings; and the short arm adapted to be moved to a pre-determined position on one of said strings.

ALBERT J. RUPP.

References Cited in the file of this patent UNITED STATES PATENTS 

